Pneumatic governor.



B. S. AIKMAN. PNEUMAT1C GOVERNOR. APPLICATION man 1uLY31.1911.

PatentedSept. 21, 1915.

2 SHEETS-SHED B. S` AlKMAN. PNEUMATIC GOVERNOR. APPUCATION man JULY3|,.1911.

1,153,879. PntentedSept. 21, 191.3.

2 SHEETS-SHEE 2.

UNITED srars BURTONS. AIKMAN, OF'CHICAGO, ILLINOS, ASSIGNOR. TO

runnin-erro Govnanoa.

Tok all 107mm t may concern.'

Be it known that I, BURTON S. AIKMAN, a citizen of the United States,residing at hicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Pneumatic Governors, ofwhich the following is a full, clear, concise, and eXact description,reference being had to the-accompanying drawings, forming a part of thisspecification.

My invention relates to controlling devices, more` particularlypneumatic governors, such as are employed in connection with aircompressing mechanism to control the starting and stopping of the devicefor operating the air-compressing mechanism,

.so that a substantially constant pressure In systems of this may bemaintained. kind, compressed air is employed as an operating fluid, and,while there are frequent withdrawals from the supply of the compressedair, it is necessary that there be a substantially and practicallyconstant pressure at all times. In the present day, these arrangementsare employed very considerably in electric railway systems, particularlyfor 'the purpose of operating thebrake equipments. vA motor compressoris connected with a supply tank to m/aintain therein a constant supplyof compressed air at the required pressure, this tank being connectedwith the brake cylinders through a valve, and the motor being controlledto start and stop in accordance with certain variations in pressure.

Thesubject matter of my invention is a governing-unit, which comprisesessentially a switch and means for closing this switch when the pressurein the supply tank has been reduced to a minimum,and opening it when thepressurehas again reached a predetermined maximum. This switch is eitherdirectly in the circuit of the motor for' operating the compressor, orin a local control circuit, automatic means being usually provided forplacing the load upon the motor gradually, rather than suddenly. Theparticular nature of the connection between the controlling unit and themotor does not concern this invention, and I shall make no specificreference thereto. In fact, the entire invention herein is confine to agovernor yer se, and thisy description will be so confined, except as itis necessary to refer to the other parts so that the controlling unititself Specification of Letters Patent.

Application filed July 3l., 1911.

course, apparent that it is only automatically, and

Fatented Sept. 21, 31915. serial no. 641,417.

lt is, of desirable, but in this day absolutely necessary, that thecompressor motor be controlled entirely the prior art is replete withdevices for securing this result mechanically or electrically.

t is one of the important objects of my. invention to provide a governorwhich is of simple construction, and which does not rely upon nemarginal operation.

lt is a further object of my invention to provide a governor which willbe quick actmay I be properly understood.

NATIONAL BRAKE 85 ELEC- i esv ing, that is, will make and break A theelectrical contacts quickly.

lt is also my object to do away with valves as much as possible; infact, I employ but one valve, and this valve is of simple constructionand of positive operation.

lt is my furtherpurpose to provide a device in which the wearing partsare few and are easily accessible for the purposes of inspection andrepair.

Other features of construction, arrangement and operation will becomeapparent to those skilled in the art as this description proceeds.

My invention is embodied in the structureillustrated in theaccompanyingv drawings, in which,-

Figure l is a side elevational view thereof; Fig. 2 is a plan viewthereof, with the cover removed; Fig. 3 is a sectional view taken on theplane of the line 3 3 of Fig. 2 and looking in the direction indicatedby the arrows; Fig. 4 is a sectional View taken' on the plane of theline 4-4 of Fig. E2 and looking' in the direction indicated by thearrows; and F ig'. will be referred to later.

Like reference characters are applied to the same parts throughout thevarious figures.

The body 6 of the casing is primarily in the form of a shelf, which canbe mounted in any suitable manner. rfhis shelf has the upright sideparts 7, 7, ,which are spanned at the top by means of a secondary shelfor bridge 8. The part 6 is provided with a circular opening 9, beneathwhich a diaphragm l0, of rubber or similar material, is clamped, bymeans of a casting 1l, bolts l2, 12 passing through the casting 1l andthe part 6 in order i to assemble the parts. The casting 1l forms thediaphragm chamber 13, below the' dia- 5 is a detail view which fstem 19,

phragm 10, and this chamber is provided with an outlet 14, extendingthrough a pipe coupling part 15, for connection with the compressed-airreservoir, as will be pointed out'imore fully later.

Mountd upon the diaphragm 10 is the piston member 16, this member havinga downwardly extending stem 17 passing through the diaphragm for thereception of a clamping ,nut 18, and in this way the piston is firmlysecured to the diaphragm. The pisl ton member haslalso an upwardlyextending which is slightly enlarged at the top and which slides with apiston fit in a corresponding alining opening 20 in the bridgef8. Astout coiled springl 21 is disposed between the top'of the piston member16 and the under side of the bridge 8, a collar 22 intervening, as bestshown in Figs. 3 andy 4. The spring is adjusted by screws This springtends to move the plunger downwardly, and it will be noted that thisaction is against the working tendency of the pressure in .thereservoir. The downward lmovement of the piston member is positivelylimited by a cap 23 which-has threaded engagement with the top of thestem 19 and which engages the upper side of the bridge 8, as illustratedin the drawings.

' structure,

This cap has a further function which will be described presently. Thepiston Vmember has an axial bore 24 extending entirely therethrough,this bore thus opening into the diaphragm chamber 13. Toward the top,the bore 24 is enlarged for the reception of'a thimble 25, which formspart of a valve This thimble is driven in the enlarged part of the bore,and is thus rmly held in place. A tubular member 26 is arranged to slidein the enlarged part of the bore in the piston member, and is providedat its lower end with an inwardly extending flange 27 which supports thevalve-seat packing 28, held in place by -means of a plug 29. The flangeslides on the outside of the thimble 25 and is provided with by-passes30, 30, which are open whenever the v alve packing is off the top of thepart 25, and 'closed whenever the valve packing is down upon it.

Secured upon each of the upright side pieces 7, 7 is a bracket, 31, andthese brackets provide bearings forthe shafts 32 and 33. Mounted uponthe s aft 32 is a trigger 34, one arm of this trigger extending over thetop of the bridge and down into the piston member so as to bear upon theplug 29, as clearly illustrated in Fig. 3. The other arm `of thistrigger is engaged on its under sidespring 35 is to raise that arm ofthe trigger and which I shall term a valve with which it is in contactso as to force the other arm down upon the plug 29. Upon the shaft 33, acircuit controlling lever 38 is mounted, this circuit controlling leverbeing broadly in the form of a bell crank lever, and having one armthereof in latch relation withthe trigger 34, as will be describedpresently. The other arm extends forwardly, and `at its forward end itis provided with a double insulating block 39 secured thereto by meansof a screw 40.

spring steel plate 41 is clamped between the two parts of the insulatingblock, the arrangement being reinforced by a sleeve 42, as shown in Fig.5, arrangement carries the electric contacrJ member 43. The contact armwhich has just been described extends forwardly through a suitableopening into a flaring box 44 of some fireproof material, this` boxbeing carried upon the body 6 by means of screws 45, 45. The stationarycontact member 46 is secured toa connector 47 by means of a 4screw 48,this connector being carried upon the box 44 by means of screws 49, 49.In Fig. 3 the movable contact 43 and the stationary contact 46 are shownto be in engagement, and it is pertinent to point out at this time thatysuch engagement is against the natural tension of a spring 50 which isdisposed between the bridge 8 and the under side of the forward arm ofthe circuit controlling lever 38. This spring is prevented fromexpanding by reason of the engagement of the downwardly extending arm othe circuit controlling lever with the shoulder 51 on the trigger A34.The engaging parts just described are reinforced by hardf iocened steelplates 52 and 53, respectively,

since this engagement is an important catch or trigger engagement uponwhich the operation of the device depends. So long as the trigger 34 isin the position shown in Fig. 3, it will be impossible forthe contactsto separate, and it is not until the spring 50 is allowed to expand thatsuch a result occurs.

i `he cap 23 which has hereinbefore been referred to isprovided uponeach side with an upward extension 54, between which a cross rod 55passing over the circuit controllin lever 38 is mounted. The circuitcontro ing lever 38 is provided with a hardened steel wearing plate 5Gunder-the cross rod 55, so as to form a good wearing surface, since thislever is adapted to be engaged by the rod to bring the electric contactstogether in the operation of the device, as will be described presently.

The box 44 is an arc chute for confining the flame that might occur uponthe separation ofthe contacts, and in orderto blow out the arc so far aspossible, I provide an electro-magnet spool 57 carried upon side pieces58, 58 which form magnet poles, and which have extensions 59, 59 whichare megeve clamped in place by the screws 45, 45. A liber or asbestosbarrier 60 is secured in front of the arc chute upon theinside of thehood 61 which incloses the entire mechanism, and which is pivoted at 62so that it may 'be easily raised to reveal the interior. Upon the fronto-f the hood a keeper 62 is provided, and this keeper carries a ring 63lll' l the other operating so held that the -electromagnet spool.

upon which a spring handle 64 is pivoted. This spring handle has twoengaging surfaces 65 and 66 for engaging a lug 67 on the part 6, and thesurface 65is nearer the pivot point than the surface 66. When the ring63 is swung over the lug 67, the handle is surface 65 may easily slip bythe lug 67, and after the ring is in the position'L shown in Fig. 1, thehandle is turned back so that the surface 66 will engage the under sideof the'lug. This springs the ring, and the parts are held tightlyclosed. P

' A suitable conductor 68 leads from the spring plate 41, and, guided inan opening 69 in a lug 70 on the body of the device, it passes out ofthe casing. l The connector 47 has a lead 71 extending therefrom, andthis lead connects with one terminal of the The other terminal of thespool is connected with a lead 72, which 'passes out of the casingthrough an opening in the bushing 73. l l

I shall now describe the operation of my improved device:

It will be remembered that the diaphragm chamber 13 is always atreservoir pressure, and this is through a choke opening. When there isno pressure in the reservoir thel its lower position and all parts arein the position shown in Fig. 3. This is the position which closestogether the contacts 43 and 46, and which thus closes the motorcircuit. As the motor operates, the air compressor builds up thepressure in the reservoir, and consequently the pressure inthe diaphragmchamber 13 is'gradually raised. As the pressure builds up, the diaphragml0 rises against the combined tension of the springs 21-and It willbe-seen thatas the diaphragm rises, the piston also rises and thetrigger 34 is turned in, a clockwise direction F ig. 3)., so that thearea ofthe engagement between the shoulder 51 and the downwardlyextending' arm of the lever 38 becomes less and less. When the pressurehas risen to a predetermined maximum-that is, when the critical point isreachedthe circuit controlling lever' is released from the shoulder 51andthe spring 50, now free to expand,

diaphragm 10 is in throws up that side of the lever to place the vthereservoir at the vrequired pressure-the pressure which is necessary toproperly op- .tent, bringing erate the brakes. As the compressed air isused, the pressure is gradually lowered, and it will be understoodpresently that my device operates to throw the contacts together againwhen the predetermined minimum pressure has been reached. This operationis as follows: It will be seen that when the downwardly extending arm ofthecircuit controllinglever is engaged by the shelf 51a of the trigger34, the spring 35 can no longer assist the spring 21, and it will beclear that a lesser pressure will keep the diaphragm in its raisedposition, that is, a lesser pressure than it required to get it there.However, the parts are so adjusted that when the required minimumpressure has been reached, the diaphragm will begin to descend under theinfluence of gravity and the spring 21. It will be seen that when thediaphragm is in its upper position, the plug 29 of the valve arrangementengages the forward arm of the trigger, and the bypasses 30, 30 are heldclosed. Just as soon as the diaphragm begins to descend, however, theseby-passes are free to open, since the trigger cannot follow the plug,due to the engagement between the shelf 5ln and the downwardly extendingarm of the circuit controlling lever. Thus very quickly does the air inthe diaphragm chamber 13 rush up through the bore, 24 and out throughthe by-passes 30, 30 to the interior of the casing, which is freelyexposed to the atmosphere-and thus very -quickly is the pressure underthe diaphragm reduced (due to the choke opening) so that the spring 21may suddenly expand to a considerable eX- down the pressure, andlowering at the same time the'cross rod 55. This rod engages theforwardly yextending arm of the circuit controlling lever and quicklybrings it down so as to close the contacts 43 and 46 together and tobring the downwardly extending arm of the lever over into such Apositionthat the rearward arm of the trigger 34 may spring 35 so that the gagethe downwardly circuit controlling lever, the parts being now back inthe position shown in Fig. 3. Then again does the motor begin to run andthe pressure to rise, as has been described, and the cycle of operationsis repeated.

shoulder 51 may en- T claim as new and desire to secure byextending armof theA rise under the tension of the position, a circuit controllinglever having a catch for limiting the movement of said trigger lever toallow release of the valve upon inward movement of the plunger due to adecrease of pressure in the fluid pressure chamber and means on saidplunger to move said circuit controlling lever to release said triggerlever when said plunger moves farther inward, due to release of pressureby opening of the valve.

3. In a' fluid pressure governor, a circuit controlling lever having anopen and a closed position, said lever provided with l spring means forbiasing the lever toward one of said positions, a trigger for engagingsaid lever and holding it in one of said positions, said triggerprovided with spring means for holding it in engaging position` amovable fluid pressure responsive element for moving said lever, a valvefor opening and 'closing a port controlling the pressure on saidelement, said trigger having means for governing the positionof saidvalve and a connection between said fluid pressure responsive elementand said circuit controlling v lever.

4. In a fluid pressure governor, a circuit controlling lever, said leveraving spring means tending to move it to the open circuit position, atrigger having a latch for holding said lever in closed circuitposition, said trigger having spring means for holding the same inposition to hold said lever, a movable fluid pressure controlledelement, a fluid lpressure chamber communicating with said element, saidchamber having a restricted inlet for supplying fluid under pressurethereto, a valve governing an opening in said chamber, said triggerhaving means for holding said valve in closed position and a connectionbetween said circuit controlling lever and said fluid pressure element.

5. In a fluid pressure governor, a fluid pressure chamber having arestricted inlet, a valve controlling the pressure in said chamber, amovable fluid pressure controlled element, subject to the pressurein`said cham-Y ber, a spring urging said element against the pressure insaid chamber, a circuit controlling lever having a spring tending tomove it to the open circuit position, a con- 'nection between, saidlever and -said fluid.

pressure controlled element, said lever being operated by said firstspring through valve being controlled jointly by said trig-l ger and bysaid fluid pressure controlled element.

6. In a fluid pressure governor, a fluid pressure chamber having arestricted inlet, a fluid pressure element, a spring for movement ofsaid element, a valve on said element, having communication with saidchamber, a spring pressed trigger controlled by the movement of saidvalve, said valve held closed by said trigger, a circuit controllinglever held in closed position by said trigger, a spring to open saidcircuit controlling lever when said trigger releases the same, saidlev'er controlling the trigger to prevent movement thereof, and meansconnected to said elementto move said lever to closed circuit positionwhen said valve is open.

7. In a fluid pressure governor, a 'fixed and a movable contact, a leverbearing said movable contact, a catch on said lever, a fluid pressurechamber, a fluid pressure controlled element, a restricted inlet openinginto said chamber, a valve on said element controlling the pressure insaid chamber, a trigger engaging the catch on said lever, said triggerhaving engagement with said valve, a spring urging said trigger againstsaid valve to retain the same in closed position, said catch of thelever preventing the movement of the means controlled by opening of saidvalve to move said lever to closed position.

8. In a Vfluid pressure governor, a fixed anda movable contact, a leverbearing said movable contact, a fluid pressure chamber, a fluid pressurecontrolled'element, a restricted inlet for said chamber, a movable valvecontrolling the pressure in said chamber mounted on said element, saidvalve normally closed, a spring controlled trigger, a spring for saidtrigger, exerting a pressure upon said valve to close the same, and toresist the fluid pressure upon said element, an independent springresisting the pressure of the fluid upon said element, said circuitcontrolling lever being provided with a catch engaging said trigger-torender said first spring inoperative to exert pressure on said element.

9. In a fluid pressure govern-or, a circuit controlling lever having a.catch, a trigger for engaging said catch to hold said lever in closedposition, a fluid pressure controlled element controlling the lever andthe trigsure element, a plurality of resilient means v v element, and avalve cooperating with said Aso y releasing the pressure in saidtrigger, a spring for pressing said trigger for resisting the movementof the fluid pressure element, a spring for said lever forcing the leverto open position when said trigger is operated, one of said resilientmeans being connected to said trigger, and rendered inoperative to eXerta resisting pressure upon said element when ,the trigger is operated,and a connectionA between said element and the lever for moving thelever to closed circuit position.

10. In a pneumatic governor a stationary contact, a lever, a movablecontact mounted on said lever, spring means urging said lever to opencircuit position, a trigger having a latch controlling said lever, afluid pressure controlled means to trip said trigger, a spring forholding said trigger in position to catch the lever, said springopposing the movement of said fluid pressure means, a valve seat on saidfluid pressure seat, said valve being held upon its seat by saidtrigger.

11. In a fluid pressure governor, a stationary contact, a lever, amovable contact mounted upon said lever, spring means urging said leverto open circuit position, a trigger having a latch for holding saidlever in closed circuit position, a fluid pressure chamber havingmovable pressure controlled means to trip said trigger, a resettingconnection between said lever and said fluid pressure controlled means,spring means operating through said resetting connection upon-reductionof pressure in saidchamber to reset the circuit controlling lever andvalve means controlled by said trigger forreducing the pressure uponsaid fluid pressure means.

12. In a fluid pressure governor, a'iiuidv pressure chamber. a diaphragmforming a wall of said chamber, a piston member connected to saiddiaphragm, aspring tending to force said piston inward, a pivotedtrigger lever, a valve having a seat on said piston, said valvecontrolling the pressure in said chamber, a spring pressing said triggerinto engagement with said valve to holdf same on itsseat on said pistonto assist in the inward movement of said piston, contact mechanismcontrolled by said trigger, and means for operating said contactmechanism, and for cutting said second named spring out ,of action whenthe piston has been moved a predetermined amount.

13. In a fluid pressure governor a vfluid pressure chamber, a movablefluid pressure responsive element subject to the pressure in saidchamber, a spring tending to move said element inward against v`saidfluid pressure, a valve having a passage communicating with saidchamber, opening of said valve chamber, a

'against said valve and tending to move said said chamber,

pressure chamber, having a restricted inlet,

a piston member subject to pressure in said chamber, a spring tending tomove said piston inward, a valve on said piston, said valve having apassage for releasing the pressure in said chamber, a stationarycontact, a lever having a movable contact, a trigger having a latch forengagingsaid contact lever, a connectionbetween said piston member andsaid trigger, and la connection between said lever and said spring.

15. In a fluid pressure governor, a circuit controlling lever, a catchfor said lever, a trigger, a catch on said trigger for cooperating withthe catch on said lever, a spring for said trigger, said spring tendingto hold said catches in engagement, a fluid pressure chamber, a fluidpressure controlled element movable by increase of pressure in saidchamber to trip said trigger,a spring for said element to resist thepressure in said chamber, a spring for said circuit controlling lever,said latter spring tending to move said lever to open circuit position,a valve communicating with said chamber, said valve being operable torelieve the pressure in said chamber and being normally held closed bysaid trigger, said valve having a valve seat upon said movable elementand a connection between said Huid pressure element and said lever.

In a fluid pressure governor, a fluid pressure chamber, a movable fluidpressure controlledelement governed by pressure in said chamber, avalve, a port communicating with said chamber, said port beingcontrolled by said valve, a circuit controlling lever, a springtherefor, a trigger lever, a lspring-therefor, saidcircuit controllingle- .ver and said trigger lever having interlocking means, a connectionfrom said pressure controlled element to said circuit controlling leverand a connection between said trigger and said pressure controlledelement.

In a fluid pressure governor, a fluid pressure chamber, a. movablepressure controlled element, subject to the pressure in a valve `forrelieving the pressure in said chamber, a spring for moving said elementinward, a trigger, a spring for said trigger, said spring resisting theout- Ward movement-of said element and holding said valve upon its seat,aI circuit controlling lever normally held in closed position aby saidtrigger and an operative connection from said element to said lever.

18. In a fluid pressure' governor, a fluid preSSllre chamber, a'pistonmember subject to the pressure in said chamber, a spring Jfor movingsaid piston inward, a stem connected to said piston, a valve on saidstem, a passage through said stem connecting said valve and saidchamber, a trigger lever pivoted at a lixed point adjacent, said stem,and having one arm bearing upon said valve, a spring connected to saidlever tending to hold said valve against its seat, and to moveV saidpiston member inward, a catch on said trigger, a circuit controllinglever, a catch on said lever for interlocking engagement with the catchon said` trigger, a spring tending to move said circuit controllinglever toopen position and a loose coupling between said piston stem andsaid circuit controlling lever to move the lever to closed circuitposition.

19. In a fluid pressurel governor, a fluid pressure responsive element,a circuit controlling lever, a trigger for holding said lever, saidtrigger controlled by the fluid pressure element, and a valve` governingthe fluid pressure on said fluid pressure element, operation of saidvalve being controlled by said trigger.

20. In a lf'luid pressure governor, a fluid pressure chamber, a movablefluid pressure responsive element, controlled 4by pressure v secondposition, and a tion, a pressure in said chamber, a valve controllingthe pressure in said chamber, an operative element'having two positions,a trigger for holding saidfoperative element in one posi-v tion, aspring to move said element'into its loose coupling from said fluidpressure element to move said operative element to its first position,said valve controlled by said trigger.

.21. In a fluid pressure governor, a switch lever provided with a latch,means for biasing said switch to-,open position, a trigger engaging saidlatch to hold the switch closed means biasing said trigger to latchingposichamber having a movable wall, an inlet and an outlet, resilientmeans acting on said wall in opposition to the pressure therein, a valvefor said outlet and means co-acting with said movable wall and triggerfor holding the valve closed and operating said trigger to release saidlatch upon increase of pressure in said chamber.

In witness whereof, I hereunto subscribe my name this 27 th day of July,A. D. 1911.

BURTON S. AIKMAN.

Witnesses:

ARTHUR I-I. BoE'r'roHnn, R. II. WEILAND.

